1. Field of the Invention
The invention relates to agricultural engineering, and in particular, it deals with the construction of harvester reels and is aimed at improving a reel rake bar, and more specifically, its time and bat blade.
2. Description of the Prior Art
Known reels are provided with wooden or metal blades which are attached by means of arms to a central shaft of the reel. They have serious disadvantages such as:
low efficiency of production process;
low productivity and unstable character of action exerted by the bat blade during operation in processing wet lodged and infested stalk mass thus resulting in considerable losses of the plant being harvested.
This is explained by the fact that the bat blade cannot lift the lodged stalk mass, hold it after cutting by the cutter device and reliably supply the stalk mass to a conveying member of the reel. The disadvantages can be partly eliminated by providing the known bat blades with tines.
Known in the art are reels in which a bat blade is made in the form of a rake bar which comprises an elongated pipe extending lengthwise of the reel and having tines, each tine being in the form of a straight rod made of a spring wire and extending through pipe perforations and a retainer loop.
The reel provided with a such rake bar can fairly work with drooping and lodged stalk mass so that a certain reduction of grain loss behind the harvester can be achieved.
However, along with the advantages, it has been found that this prior art reel has serious disadvantages because, the tine rod being straight, it cannot hold the stalk mass efficiently enough after cutting, and the stalks move and slip away from the tine thus resulting in a loss with cut stalks.
The tine of the rake bar of this type is also deficient in that, in operation in the fields with inadequate stalk plant cultivation, the tine can be so deformed as not to return to its original geometry, i.e. a residual deformation can occur which also results in an impaired quality of the process and in lower reliability in operation.
This rake bar is also deficient in a high labour effort for its manufacture as perforation should be made in the pipe for mounting the tines.
Known in the art is a construction of a more versatile rake bar which is free from the above disadvantages and which comprises a tubular shaft with bat blades and tines attached thereto and made of a spring steel of round section, the tines being arcuated with the concavity in the direction of rotation of the reel, a shock absorber in the form of one or two spiral flights, and a fastener member in the form of a loop surrounding the tubular shaft and the bat blade and secured by the spiral flight.
The rake bar having the spring tines with a shock absorber and with the rod which is arcuated can engage and lift lodged stalk mass in a very efficient manner hold it after cutting and feed to the reel conveyor.
The tine of this rake bar has a sufficient reliability in operation as the shock absorber in the form of a spiral flight allows the tine to deflect at a large enough angle when coming across an obstacle and to return to the initial position after passing by the obstacle without any change in shape owing to the elasticity of the spiral flight.
Owing to this construction of the tine, breakage of the tine becomes very unlikely.
However, the provision of the spiral flight in the construction of the tine, apart from positive properties of the tine, namely restoration of its shape, brings about an undesirable phenomenon, and namely, an impact action upon the stalk mass at the moment the tine emerges from the lodged mass or returns to the initial position after passage by an obstacle because of a high rate of the elastic rebound which causes grain losses through thrashing out.
In addition, the spiral flight causes pinching of the stalks thus bringing about stalk mass winding on the reel rake bar and disrupting the process carried out by the rake bar. In order to eliminate this disadvantage, transverse cuts are made on the bat blade, adjacent to the lower edge thereof, to partly receive the spiral flight thus slightly lowering the probability of pinching of the stalks between the flights. However, the cuts in the bat blade lower its strength and reliability in operation. The rake bars of this type are also deficient in that they require high labour effort for manufacture, installation and removal of the tines and have a high cost of manufacture.
All the abovedescribed constructions of the reel rake bars with steel tines have a common disadvantage residing in that tines getting into the cutter device cause its breakage.
Also known in the art is a reel rake bar having tines made of a structural plastic such as nylon.
A tine of such a rake bar comprises a thin rod arcuated with its concavity facing in the direction of rotation of the reel and having a varying I-beam cross-section lengthwise and a fastener member for attaching it to a bat blade, which comprises a V-shaped cut terminating in its lower portion in a rectangular mounting channel, the fastener having legs of different height, one, longer or rear leg having an end button (U.S. Pat. No. 3,796,030).
The bat blade of this rake bar is a wedge-shaped cross-section defining a relatively thin edge in the lower part thereof which is equidistant with respect to the mounting channel of the fastener member of the tine.
A rear wall of the bat blade has a circular hole.
To install the tine, it is applied to the lower part of the bat blade so that the button is received in the hole of the rear wall of the bat blade and the lower edge of the bat blade is received in the mounting channel of the tine.
This construction of the rake bar does not rule out different methods of the tine fastening to the bat blade, e.g. by means of bolts.
The rake bar having polymeric tines makes it possible to achieve a substantial reduction of metal weight of the construction and to lower labour effort in the manufacture, assembly and dismanting of the tines.
If the polymeric tine gets into the cutter device, the tine is easily cut without causing any damage to the cutter device.
However, the rake bar with polymeric tines is deficient in that a large concentration of mass in the zone of transition from the tine rod to its fastener member cannot enable elastic deformation of the tine with a large enough amplitude when coming across an obstacle without compromising its integrity.
Another disadvantage of such a tine of a rake bar resides in that when its vertex engages with a heavy lodged stalk mass, the tine is twisted in the vertical plane thus lowering its reliability in operation and disrupting the process with a loss of harvest. As the working surface of the prior art tine is formed by the flange of the I-beam section, rather than by the web, the losses through cut stalks increase.
An increased friction occurs on this surface in the zone of engagement between the stalk mass and the tine to hamper the movement of the cut stalk mass to the reel conveyor so that a part of the cut stalks is entrained by the tines and thrown over the reel forwardly and over the rear wall of the harvester.
Reliability of the attachment of the tines to the bat blade in the prior art rake bar is low. This is especially remarkable in harvesting under severe conditions (lodged plants, wet stalk mass, etc.). When the tine engages such a stalk mass, forces exerted by the stalk mass tend to deform the tine in the direction opposite to the direction of rotation of the reel. These forces are taken-up by the fastener member. As a result, the tine is broken adjacent to the fastener member, and deformation of the shorter front-end leg which is not fastened to the blade takes place. Under such conditions, all forces acting upon the tine rod are taken-up by the longer rear leg, and the button engages from the blade hole so that the tine is lost.
Therefore, the above described constructions of the reel rake bars are deficient in that they cannot effectively act upon the stalk mass thus bringing about unwarranted grain losses, lower productivity of the harvester and low reliability in operation, the metal weight of the structure being increased.